The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 04, 2014
Filed:
Oct. 28, 2011
Jian Liu, Palo Alto, CA (US);
Philip Lynn Leichty, Rochester, MN (US);
How Tung Lim, San Jose, CA (US);
John Michael Terry, San Jose, CA (US);
Mahesh Srinivasa Maddury, San Jose, CA (US);
Wing Cheung, Fremont, CA (US);
Kung Ling Ko, Union City, CA (US);
Jian Liu, Palo Alto, CA (US);
Philip Lynn Leichty, Rochester, MN (US);
How Tung Lim, San Jose, CA (US);
John Michael Terry, San Jose, CA (US);
Mahesh Srinivasa Maddury, San Jose, CA (US);
Wing Cheung, Fremont, CA (US);
Kung Ling Ko, Union City, CA (US);
Brocade Communications Systems, Inc., San Jose, CA (US);
Abstract
A LPM search engine includes a plurality of exact match (EXM) engines and a moderately sized TCAM. Each EXM engine uses a prefix bitmap scheme that allows the EXM engine to cover multiple consecutive prefix lengths. Thus, instead of covering one prefix length L per EXM engine, the prefix bitmap scheme enables each EXM engine to cover entries having prefix lengths of L, L+1, L+2 and L+3, for example. As a result, fewer EXM engines are potentially underutilized, which effectively reduces quantization loss. Each EXM engine provides a search result with a determined fixed latency when using the prefix bitmap scheme. The results of multiple EXM engines and the moderately sized TCAM are combined to provide a single search result, representative of the longest prefix match. In one embodiment, the LPM search engine supports 32-bit IPv4 (or 128-bit IPv6) search keys, each having associated 15-bit level 3 VPN identification values.